Considering the present environmental problems involving both waste disposal and its effect upon the quality of water, it is necessary to test groundwater, surface water, water supplies, waste water and/or industrial liquid waste to determine the concentration of any contaminants therein. It is desirable to determine the concentration of organic compounds in water so that the deleterious effects of these contaminants can be minimized, thereby maintaining and improving the quality of our water supplies. Many non-purgable hydrophobic organic compounds are known to contaminate water supplies. Polychlorinated biphenyls (PCBs), polynuclear aromatic hydrocarbons (PAHs), dioxins, petroleum materials, and pesticides, for example, are just some of these commonly known organic compounds.
There are currently available modern analytical instruments which are capable of detecting and quantifying minute amounts of organic compounds. Presently, however, the testing of water for the presence of organic compounds is commonly performed by transporting samples of water to various testing apparatuses, usually located in a laboratory. This procedure, however, is labor intensive.
One problem with the current testing and measurement of organic compounds in water is that the concentration of these organic compounds in water may be minute, making it difficult for analytical devices to accurately measure the concentration levels. As a result, it is frequently necessary to increase the concentration of the organic compounds in order to measure their concentration. This is accomplished by performing an extraction process in the laboratory, which may increase the cost of water analysis and also increase the labor involved in such analysis.
It is, therefore, an object of the present invention to provide a method and apparatus for an inexpensive and simple determination of the presence and amount of organic compounds in water without the necessity of transporting a sample of the water to a laboratory. In this manner, larger water samples can be analyzed which will improve detection limits.
It is also an object of the subject invention to provide a method and apparatus which eliminate the extraction process normally performed in a laboratory.
The subject invention accomplishes these objectives by providing a method and apparatus for removing organic compounds from water in-situ. The organic compounds are collected in a solvent retained within an apparatus having non-porous membranes, and such solvent can then be analyzed directly within a laboratory. This eliminates the extraction step in the laboratory analysis of most water samples, thus potentially decreasing the cost of water analysis.
The subject invention further provides an apparatus which will greatly enhance the effectiveness of field monitoring programs by allowing collection of more samples and the achievement of better detection limits on the samples collected. This is because the subject apparatus can be placed in water and left there for a much longer amount of time, allowing for larger water samples to be analyzed.
Sodergren, A., Environ. Sci. Technol. 21 855-859 (1987) discloses a solvent-filled dialysis membrane which simulates the uptake of pollutants by aquatic organisms. Sodergren uses dialysis membranes filled with hexane to accumulate persistent lipophilic pollutants in a way similar to that of aquatic organisms.